High lift slotted flap



y 20, 1965 A. ALVAREZ-CALDERON 3,195,836

HIGH LIFT SLOTTED FLAP Original Filed April 16, 1962 2 Sheets-Sheet 'l iz-mmmow y 1965 A. ALVAREZ-CALDERO N 3,195,836

. HIGH LIFT SLOTTED FLAP Original Filed April 16, 1962 2 heetst 2 United States Patent 3,195,836 HHGH LEFT LOTTED FLAP Alberto Alvarez-Caidern, 156i) Castilieia Sh, Pain Aito, Calif.

Original application Apr. 16, 1962, Ser. No. 187,963. Divided and this application May 24, 1963, Ser. No. 283,114

Claims. (Ci. 244-42) This application is a division of my copending application, Serial Number 187,903, filed April 16, 1962, for Leading Edge Flap and Apparatus Thereof.

The present invention is related to high-lift leading edge devices for lifting surfaces, wings and the like. More specifically, this invention concerns new and superior structures for slotted leading edge flaps on aircraft wings.

High lift leading edge devices for wings have been known since the early days of aviation. The recent emphasis on the use of thin wings for high speed aircraft, and the use of powerful trailing edge flaps with boundary layer control, has created special problems of flow separation and deterioration at leading edge of wings at large lift coefficients. As a result of these problems, numerous high lift leading edge devices are now needed and used in aircraft.

These leading edge high lift devices can be aerodynamically grouped into two categories: One is the unslotted camber-changing structures at the leading edge of the wing, for instance the well known Kruger flap and the droop leading edges. These high lift devices are discussed in the book Theory of Wing Sections, by I. H. Abbot and A. E. Von Docnhoif, page 230, published by Dover Publications, Inc. These types of structure improve the shape of the airfoil for high lift flows but do not provide reenergizing of the flow or of the boundary layer on the wing. As is well known the Kruger flap is one of the simplest of the un-slotted leading edge devices. it consists in a spanwise pivoted door in the leading edge of the wing and is mechanically similar to the well known trailing edge split flap. From the aerodynamic aspect, the Kruger flap increases the lift coefficient and angle of attack of thin wings by values smaller than those that could be obtained with slotted leading edge flaps of an appropriate shape.

For the case of medium thick wings, the effects of the Kruger flap are not large and may be even detrimental. The Kruger type of fiap is commonly used in the thin wings of some high speed jet aircraft to obtain some improvement in lift because of its mechanical simplicity and also because it permits a smooth uninterrupted upper surfaie for the wing.

A second group of leading edge devices are those which not only provide for a camber increase in the wing, but also provide for flow and boundary layer reenergizing by means of a spanwise slot at its forward position. One such device called a slat is shown in FIG. 141, page 236 of the aforementioned reference.

The slotted leading edge devices which increase the Wings camber, because of its flow reenergizing feature, provide a larger increment of lift coefficient and angle of attack than those possible with unslotted camber increasing lea-ding edge devices. The feature of flow reeuergizing is specially important at large absolute magnitudes of lift coefficients, for in this condition the induced upwash at the leading edge of the wing is large. This condition would exist, for example, in the case of a trailing edge flap with boundary layer control, an STOL airplane, or a tilt wing VTOL airplane. Large localized'angles of attack would also favor the use of a slotted leading edge device.

However, the mechanical complexities of slotted lead- 3,195,836 Patented July 20, 1965 ing edge devices which retract smoothly in relation to the wings surface for high speed flight are serious. Usually it is required that the slat unlike the pivoted Kruger flap, should translate forward and downwards as well as rotate downwards. Additionally, even in the best arrangements proposed so far for slotted leading edge devices, in the slat retracted position there exists a surface interruption in the upper surface of the wing which increases drag at high speed. This interruption is important since it precipitates a turbulent boundary layer in the upper wing surface and it also offers a localized drag increment for typical construction methods.

It is therefore evident that the slotted leading edge flaps or slats as proposed so far have structural complications and drag disadvantages which in many cases have greater weight than their special high lift advantages. It is evident that a superior mechanical leading edge device would be one which would combine the structural and mechanical advantages of the Kruger type of flap (2. simple pivotal connection, no translation on tracks and no interruptions of the skin in the upper wing surface for high speed) with the aerodynamic advantages of a slotted leading edge flap or slat. (Flow and boundary layer reenergizing at the wings leading edge to produce greater lifts and range of angles of attack.)

I have invented such a leading edge structure which combines the areodynamic and structural advantages of each of the types of leading edge devices in unique cooperation between the wing and the device. In addition, my slotted leading edge flap is superior because there is no abrupt change of slope on the wings upper surface like that present in wings with slats at the wing location corresponding to the trailing edge of the retracted slat.

Moreover, my improved plotted high lift leading edge device can have a cross-sectional shape substantially independent from the cross-sectional shape of the upper leading edge portion of the basic airfoil. This characteristic makes it superior for thin high speed airfoils since its shape need not conform to that of the thin wing leading edge as is usually the case with convention-a1 slats. For thicker wings, this also permits to select the basic wing camber for cruising conditions but yet retain a leading edge flap cross-sectional shape of large curvature suitable for very high lifts.

It is one purpose of this invention to provide structure for a superior pivoted slotted leading edge flap which retracts into the lower forward portion of the wing.

Yet another purpose of the invention is to provide such a structure in which the curvature and leading edge radius of the flap is greater than those of the wing.

Another object of this invention is to provide a slotted pivoted leading edge device which can be incorporated easily into existing aircraft without serious modification of their existing wing structure.

Yet one more object of this invention is to provide a slotted leading edge shape structure in which the pivotal connection between the wing and the flap falls within the air foils contour Yet another object of this invention is to provide a slotted pivoted leading edge device or" the type described that can be mounted on the wing chordwise fences.

One more object of the invention is to provide a structure for a double-slotted leading edge pivoted flap of superior aerodynamic characteristics.

Yet one more object of the invention is to provide a retract-able pivoted flap which when extended increases the effective curvature of the wing leading edge proper.

These and other object and features of the invention will be more readily apparent from a perusal of the description of the embodiments of the structures illustrated in the accompanying drawings, in which:

FIGURE 1 shows a cross-sectional view of my pivoted areasae slotted leading edge flap. installed in the forward lower portion of a wing. Y

FIG. 1A shows a fiap detail of FIG. 1.

FIG. 2 shows a cross-section view of my device installed on a thinner wing; the figure also illustrates modification of the new flap with a small Kruger type of auxiliary flap.

FIG. 3 shows in similar .cross-sectional-view my design incorporated in a very thin wing andin combination with a droop nose. FIG. 4 shows a cross-section view ofmy pivoted leading edge flap mounted externally as a high lift modification for an existing wing.

FIG. 5shows a cross-sectional view of my pivoted leading edge flap installed as a high speed modification for an existing wing whereby the camber and leading edge size of the existing wing are reduced. Yet high lift is improved with the device.

FIGURE 6 is an auxiliary figure showing the flap of FIGURE 5, incorporating a collapsible flap leading edge e tube.

FIGURE 7 shows a cross-sectional view of my flap illustrated retracted inside a wing in a double-slotted configuration and with an auxiliary flap door.

FIGURE 8 shows a structure similar to that of FIG- URE 7 but somewhat simplified and incorporated on the leading edge of thin wing.

FIGURE 9 shows my slotted pivoted leading edge device installed at the leading edge of a main flap and incorporated with'a wing such as to form a triple slotted fiap configuration.

FIGURE 10 shows a scale, the percent of wing chord the retracted leading edge flap 4 in position 6 wherein the surface of the flap on the side opposite to the fiap pivot axis 2 forms actually part of the airfoils surface in the high speed condition. This surface should be preferably curved as shown. The'flap has a thin edge adjacent to the pivot-as in 2, approximately below the pivot axis, and on the lower surfaceof the wing slightly to the rear of the leading edge of the wing proper. This position is indicated .by' arrow 7. Now, carefully observe that instead of hinging the {lap structurally usual and obvious point, like'say point 7 (which would result. in a Kruger flap), the hinge axis is displaced upward above edge 7 by means of previously described simple fixed flap bracket 3, to hinge position 2. Axis 2 shouldbe placed adjacent to the upper surface of the flap and away from edge 7 at a distance which for this type of geometry is approximately equal'to the gap distance between the fiap edge and the wing leading edge when the latter is in the high lift position. Thus, in the figure, the distance between .axisz and edge/7 is ab0ut.2 /2% of the wing chord.

' Additionally, however, the flap hinge axis is placed with which can be used to evaluate the proportions of FIG j URES 1, 2, 3, 4, 5, 7 and 8.

FIGURE 11 shows a structure ofthe type of FIGURE 7 but modified to incorporate suction boundary layer control. With initial reference to FIGURE 1,. I show therein a cross-sectionalviewof the nose portion of medium thick airfoil section; say of the type of the NACA 63-212, incorporating my slotted leading edge flap. Specifically, the

figure shows a forward wing portion 1, supporting a leading edge flap 4 by means of flap bracket. nects flap 4 to pivoted spanwise axis 2 located at a selected position adjacent tov the upper surface of the leading edge of. wing portion 1. My flap 4 is shown in its high lift position, increasing the camber and chord of the wing. In addition, according to the invention, the flap hinge location chosen is such that in the high lift position 4, the flaps thin edge 12 defines a slot between the flap and the leading edge of wing portion 1. The flap hinge location will be explained later. The slot should be preferably contracting in the direction of the flow as shown and of a width approximatelybetween 5 and 1 percent of the wing chord. Through the slot flows a high speed sheet and for tilt wing aircraft which have to operate with.

extremely large eifective wing angles of attack.

Observe, however, that these excellent aerodynamic features in my slotted leading edge flap have been obtained not through cumbersome structural complexities or trans- .the flaps pivot axis and the flaps surface with respect to each other" and with respect to the wing. This geometric relation can be better described with the aid of the drawings showing the flap in the high speed retracted position: it is seen that the lower surface of the wing portion 1 has a recession 5 which serves to accommodate Bracket 3 COD".

about 2 /2% of the wing chord.

respect to wing and flap as shown in the drawing such that when the flap is rotated about axis 2 by about 130 to high lift position 4, a slot between the flap and the wings leading edge is formed. The slot shown has a gap of It is the presence of the slot with its fluid re-cnergizing feature that enables aerodynamic improvement beyond those possible with an unslotted flap ofsimilar mechanical structures.

It is evident by inspection of the drawing that relatively large angular'motion of flap 4 is possible without signififixed wing position w-ill then straighten out the excess curvature by contact at point 7, and also serve as a tight pressure fit.

Another feature of interest is that the wings. lower skin in recession 5 can be shaped such as to providea highly undercambered, smooth leading edge entry for the wing portion of the slot lip which feature is very favorable for high lift. It should be observed'that in the invention, the surface, interruptions due to theretracted flap are in the wings lower surface. Thus, the local flow disturbances due'to the interruptions are damped by the favorable pressure gradient of the flow which is going from pressures higher than atmospheric to atmospheric at the wings trailing edge; and a smooth upper surface is possible for laminar flow. In contrast, flow disturbances in and/or due to surface interruptions inthe upper surface ofthe wing which exist with conventional slots, tend to amplify due to the adverse pressure gradients.

. As an alternate feature for determining the slot gap,

thin edge 12 of the flap can be reduced in length, say to position 14, whereby the slot gap can be increased in size wings, Thisfeature will be illustrated inglater figures.

lating parts (such as slats on tracks, etc.), but by virtue. of the new, ingenious, simple and superior location'of 1' I Evidently, my slotted leading edge flap maylbe actuated in any numb'erof ways known in the art and used, for plain pivoted flaps such as'split trailing edge flaps or Kruger leading edge flaps, or by the mechanism I show in my FIGUREA. J l

' Summarizing the-features of the embodiment of FIG- URE 1, it is seen that by the ingenious and superior choice of leading edge flap axis and related geometry, there is obtained a structurally simple pivoted leading edge flap which yet by virtue of its peculiar geometry, can form when extended, a high lift slot with the leading edge of the wing to increase the wing angle of attack range and lift beyond the values possible without the slot. Additionally, the shape of the flaps thin edge is favorably curved near the slot, and the wings under surface can be shaped to have high local undercamber, both of which features are beneficial for high lift.

Furthermore, tight simple fittings can be made between the flap and the Wing, due to absence of translation of the flap, and the surface interruptions are located in the wings lower surfaces where the drag disturbances are damped out quickly. With my device, the wings upper surface can then be smooth and uninterrupted. Evidently, c0nventional structural design and flap actuator mechanisms can be used to construct and operate my new slotted leading edge flap.

As an alternative structure to FIG. 1, I want to show an optional feature in the flap proper in FIG. 1A. In the thick rounded flap edge, away from the thin flap edge and the flap pivotal axis, there is shown an optional pivoted flap addition 9, pivoted at spanwise axis on the flap, and which can be deflected through are 11. It has a flap-extended spring-fixed high lift position 15, shown schematically by line 15, wherein it increases the camber of the flap itself and fixes the flap stagnation stream-line on the fiaps upper surface on the thin edge of flap portion 9. The spring mechanism may be of the type shown in the leading edge of the flap of FIG. 5 of my US. patent application Ser. No. 157,422 of Dec. 6, 1961.

Also, when the flap is extended, the under surface of the wing which mates the flap would be evidently of gentle curvatures and favorable for low drag at high lift.

Yet one more important feature of the invention which is obvious by inspection of FIG. 1, is that the device can be easily installed as a modification to existing wings in airplanes with a slight modification in the under surface.

I will now describe additional embodiments of my slotted leading edge flap on thinner wings suitable for near sonic and supersonic flight. In these additional embodiments, there are also shown in the wing portions the use of well known leading edge devices but of relatively small size which act in combination with my larger, new, slotted leading edge.

In FIG. 2, I show a partial cross-sectional View of my slotted leading edge fiap incorporated in a thinner airfoil section suitable for high speed, say of the type of the NACA 65-210. Specifically, the figure shows a forward wing portion having a slotted leading edge flap 2?: shown in a high lift position supported by means of brackets 22 to flap pivotal axis 21. Axis 21 is located adjacent to the wings upper surface and adjacent to the wings leading edge proper. The geometric relations between flap, pivot axis and wing are again described in the flapretracted position: the wings lower surface has a recession 24 which accommodates fiap 23 into retracted position 25, wherein the flaps surface opposite to this pivot axis forms part of the airfoils contour. The thin edge 33 of the flap adjacent to the pivot axis 21 is seen located to the rear of axis 21 by about 4% of the wing chord and on the wings lower surface. When the flap is pivoted about axis 21 in a clockwise direction from position 25 to high lift position 23 or 26 along arc 34, then edge 33 determines the high lift slot between the flap and the wing.

So far I have described my leading edge flap on the wing. Now I point out how the combination of my slotted leading edge flap with a small-size conventional leading edge flap, say of the Kruger type. The combination forms a unique structure which improves the shape of the high lift slot. It is seen in FIG. 2, that an auxiliary conventional Kruger type flap is mounted at leading edge axis 29 and extends to the high lift position 30. The combination of surfaces of the auxiliary flap, together with my slotted flap, determine a favorable contracting channel 28 of relatively long length and having a direction nearly perpendicular to the wings chord. The contraction ratio of the slot can be set for any position of my slotted flap 23 by varying angle 31 of the auxiliary flap. The auxiliary flap can be retracted to position 32 for high speed flight.

The combination of my slotted fiap and the conventional flap may be of particular advantage for wing flows at very large effective wing angles of attack, such as in jet winged aircraft, or near the engine pylons below a swept wing, or for STOL approaches of tilt wing airplanes.

It should be observed that as an alternate structure to auxiliary flap 30, an inflatable leading edge membrane or boot may be used in combination with slotted leading edge flap to extend the length of the slot. Since such boots are known in the art (see, for instance, US. Patent 2,934,288), they will be omitted here.

In FIGURE 3, I show an installation of my slotted leading edge flap in combination with a conventional droop nose. The combination is exemplified on a very thin airfoil, say of the type of the NACA 65006. Specifically, the figure shows a forward wing portion 40 supporting at axis 48 a conventional droop nose 47 which can move as shown by are 41 Also, in the retracted position, inside the appropriate wing recession 44, there is shown my slotted high lifht flap 45. Observe that position 45 is substantially to the rear of the leading edge of this wing, and therefore there is a fixed wing skin surface 40 between the droop nose and the retracted flap. Flap 45 is supported at axis 41 by a bracket. For intermediate lift coefficients, flap 45 is rotated clockwise about axis 41 to a position similar but beyond position 43, whereby a slot is formed on location 46 between the flap and the undefiected droop nose.

For higher lifts, the droop nose is lowered counter clockwise to position 47, and the flap is positioned in location 43, whereby a long contracting slot 50 is defined. Again, for any flap position, the slot contraction and gap may be defined with the aid of the droop nose.

As a structural refinement, for the case of swept wings, brackets 42 should preferably be installed such that their surfaces are aligned to the slot flow in the flap extended position. Since in that position the surfaces need not be perpendicular to axis 41, then the mechanical connection of the brackets at axis 41 may be made with self-aligning bearings.

As shown, the brackets in the flap extended position are located below the exhaust mouth of the slot and the local flow disturbances due to bracket non-alignment are minimized by the stabilizing contraction of the slot above the bracket.

In FIGURE 4, I show another embodiment of my invention which is particularly suitable for modification of existing wings. Specifically, I show in cross-sectional view, the forward portion of a wing having an upper surface, a leading edge, and a lower surface. External to the wings surfaces, there is shown installed my high lift slotted leading edge flap. On the wings upper surface, there is shown a fixed wing bracket 61 which is positioned as a wing fence. The wing bracket supports at pivotal connection 62, a flap bracket 63 with flap 64 shown in the high lift position. A slot 69 is defined between flap 64 and the leading edge of wing 60. For high speed flight, flap 64 is moved counter clockwise about axis 62, by retraction of push rod 71 and piston 70, to final flap position 66. The flap in position 66 forms an external streamlined bulge below the wings lower surface and a fixed flap fairing is provided to prevent flow deterioration. Flap bracket 63 is now in position 67.

It should be observed that this modification does not change the leading edge radius of the wing nor its thickness-chord ratio but only the thickness distribution and wing camber. The camber change is favorable and is not large. The entire modification to the wing is extremely simple as only external brackets and reinforcements are necessary. Significantly improved lift and angle of attack ranges are obtained with a negligible drag penalty. In FIGURE 5, I show the installation of my device as a modification on a wing whereby a new airfoil section of 1% may be closed clockwise and inwards, such that its forward edge'falls adjacent'to wing location 104. The

'door 100 may be moved by any number of ways known to those skilled in the art; for example it may be moved reduced camber and leading edge radius is obtained. 1

These reductions are useful for near sonic speed of flight as they increase the cruise Mach number and the Mach number of drag rise, and reduce adverse compressibility eifects; therefore, the modificationsare specially adaptable for existing high speed jet transports and the'like. As

can be seen, however, the high lift slow speed character- 'tion 87, wherein it forms the lowersurface of the modification glove for high speed flight.

, FIG. 6 shows a modification for the leading edge flap 86 of FIG. 5. Specifically FIG. 6 shows a portion of flap 36 and bracket 85 supporting a collapsible inflatable spanwise boot 90 which can be inflated by gas tube 92 for high lift and collapsed for high speed by releasing the gas pressureand subsequent action-of a spring or similar f incorporated to improve the high lift characteristics above those of the .originalwing. Thus, the device acts to improve both the high speed and slow speedregimes of the 7 aircraft.

structures of FIGURES I 1 In FIGURE 7, I show an embodiment of my structure optimized, for aerodynamic excellence. 'My high lift 1 as shown in relation to doors-71 and of FIGS. 6 and 7, respectively, in U.S. Patent 2,005,965, or as shown in FIGS. 5 .to 9 of U.S. Patent 2,041,688, or as shown in FIG. 2 of U.S. Patent 1,893,065. i

It should be observed thatthe structure. previously de scribed can be simplified by-making the flap of smaller size than shown without the forward vane, in which case, the size of the'door which acts as a flap fairing could be reduced substantially. This is illustrated in FIGURE 8, showing a very thin wing having my highly curved (slotted) flap 113 supported by bracket .112 to spanwise axis. 111. Thewing has a door 114 which allows emergence of the flap to high lift position 115 in which slot 116 isformed between the flaps thin edge 117 and the wings leading edge. Observe that in this structure thefiaps curvature or camber, and the flaps leading edge radius, are much larger than those of the basic wing or'than thosethat could be incorporated in a standard leading edge slat. It should be carefully observed that my slotted pivoted structure for the wing leading edge, can also housed in an exemplary manner as a retractable vane. in the nose of a trailing edge multislotted flap. For example the leading edge fiap of my FIG. .7 mounted on.a trailing edge flap as a vane would form'with the flap andwing a triple slotted flap configuration of smoothly varying camber, and a variable flap area. Similar installation with the structure of any other figure say. FIGS. 1, 2, 4 or 8, would result'in a double slotted trailing edge flap configurationof similar characteristics.

These trailing edge flap embodiments are extremely well adapted for thin wings due to their mechanical simplicity and reduced cross-sectional area in the retracted position.

The structure just described is illustrated in FIGURE 9 in the high lift position. There is shown in cross-section a1 view the trailing edge portion 120 of a wing. For this drawing, the relative wind is obviously flowing from the right side of the page to the left side, as indicated by arrow 126. In order to show clearly and in large scale the shapes and relative positions of the airfoil and fiap only therear leading edge flap-shown retractedwith a high speed'air foil of the type of the NACA.-652l0 consists essentially of .a double slotted leading. edge flap; arrangement, the cross-sectional shape of which is independent from the cross-sectional shape of the airfoils leading edge shape This freedom of choice of flap. cross -shape,;unlike the conventional slat (which has a cross-sectional shape con:

'forming to the, airfoils'leading edge shape) permits to portion 120 of the airfoil is shown. Airfoil 120 is shown provided with a trailing edge main flap 121, which may be moved. inwards of wing 120' by any standard flap mechanism. For example mechanism of FIG. 17 of French Patent 987,021 may be used as it is extremely well suitedfor my flap 121 of FIG. 9; in this case my as 123 by means of a bracket extending from the vane to pivotal axis 124'on flap 121; thisbracket is similar to I bracket 3 of my FIGURE 1.

pivoted to. its support if desired. The flap is housed.

within leading edge portion of wing 95 and in part forms a portion of the wings lower surface, the latter is faired smooth to they flap by means of door 100,.which also serves to house the flap. Tomove the flap to its high lift position, the door fairing 1&0 is moved counter clockwise along are 102 about axis 101, to allow emergence of 1 the flap. The. flap'is moved clockwise about axis 96 'along are 103 by about'135 degrees-to a high'lift position in whicha slot isformed between the thin edge of portion 98 and the wings leading edge (see, for instance, slot of FIGURE -1). Thus, the flap-wing slot, plus the fixed slot in the flap proper, form, a double slotted leading edge flap arrangement of excellent aerodynamic efficiency. When the flap is moved to the high lift position,.fairing Alternately, a trailing, edge fiap vmechanism such as shown in FIG. 23 of U.S. Patent 3,041,014..may be used for translating and rotating my flap 121 relative to my wing 120. Any other 'fiap system'suitable for Fowler type'flaps may be used, and these are well known and will not be repeated here. I will now continue the descriptionof myflap. The path of ,air by the three slots is shown as 126, 127 and Y128. To retract the flap, first the auxiliary vane'shouldbeturned clockwise about axis 124 about degreesfuntil it rests against flap 121. This vane rnotion may be accomplished by a control device of the type shown in my FIGURE 4 consisting of actuator 7ii.and piston.71. This control device, in order to move myvaneof FIG. 9 should be installed in my flap 121 to accomplish retraction of'vane 123 by clockwise angular motion ofaboutlSO degrees about axis 124 into recession of flap 121 ,The actuator may be signalled from the wing byany mechanism, for example, see FIG. 16 of French Patent 987,021 showing link 141'connected to ing to leading edge devices.

wing 7 by means of link 144. An alternate actuator may be that of FIG. of US. Patent 3,128,966 pertain- With the vane retracted, the flap structure may then be retracted inside the wing to a position shown schematically in dash lines 125, showing clearly the position of vane 123 relative to flap 121 and wing 126. The vane and leading edge portion of flap 121 are evidently housed and faired inside the trailing edge of wing 12%, with the trailing edge portion of fiap 121 complementing the trailing edge of airfoil 129 as is usual in flaps. The rear portion of the flap 121 in the retracted position 125 has been omitted however, such as not to interfere with the important vane drawing 123 and flow lines 127 and 126. With respect to the flap retracted position 125 and wing 1243, it is evident that the volume occupied by the retracted flap is small, and that when extended the curvatures, slots and area increments are extremely favorable for high lift.

In FIGURE 10, I show a scale which may be used to exemplify the relative sizes and gaps of the embodiments illustrated. The scale is presented in terms of percent of wing chord and is useful for FIGURES 1, 2, 3, 4, 5 and 7. This scale is included, however, by way of example and not by Way of limitation.

There are other variations and modifications of the structures of my high lift slotted fiap. For instance, the leading edge flap may be connected by a four-bar linkage instead of a simple pivotal connection or the flap may be located between a fuselage and a nacelle and hinged to them directly and not to the wing structure.

A large efficient boundary layer control device may be installed in the leading edge of the flap which yet will retract completely inside the wing for high speed flight. For instnace, in FIGURE 11, the forward flap portion 131 is shown having a large suction cylindrical leading edge tube 132 for boundary layer control which is effective with or without slots. It could obviously be replaced by a blowing cylindrical leading edge device having a spanwise slit to eject air, or by a spanwise rotating cylinder arrangement. Equally well in an excellent manner, such flap arrangement could be installed on a trailing edge flap in a wing. Therefore, in FIG. 11, airfoil portion 135 may represent a main trailing edge flap surface, say like 121 of FIG. 9, or wing leading edge like 1 of FIG. 1; to which element 131 may be connected by a pivoted bracket as bracket 3 of FIG. 1, or as the bracket of FIG. 9 which supports element 123 to flap 121. When flap portion 131 of FIG. 11 is retracted, it should be adapted to move in clockwise motion by about 150 degrees to a portion below airfoil portion 135 and Within the contours of the lower portion of the dash lines of FIG. 11, like position 6 in FIG. 1.

The boundary layer control devices are kriown (see, for instance, US. Patents 2,844,337 and 2,928,626). They should be installed as shown in my new ingenious flap structures shown in FIGURE 11.

Also, my slotted flap mechanism can be used for elevators, stabilizers, hydrofoils and other fluid sustained vehicles. It should be mentioned that the various structure features of the embodiments are inter-related. For instance, the wing door of FIGURE 7 can be used in the wing of FIGURE 11.

Various further modifications and alterations from those described hereinabove can obviously be made without departing from the spirit of the invention, and the foregoing is to be considered as purely exemplary application thereof. The actual scope of the invention is to be indicated by the appended claims.

I claim:

1. An aircraft wing having a trailing edge portion with an undersurface; a trailing edge flap mounted on said wing and adapted to be moved between a high speed position in which said trailing edge flap is faired with said wing adjacent to said trailing edge portion and a high lift position inclined to and external from said wing with said trailing edge flap in said high lift position having an upstream edge, an upper surface and a lower surface; a vane mounted on said trailing edge flap by means of a bracket extending from said vane and pivoted to said flap at a spanwise pivotal axis located adjacent to said upstream edge, with said vane being adapted to be moved with respect to said trailing edge flap by angular motion about said pivotal axis which inverts said vane between a retracted vane position in which said vane is trailing said upstream edge and is located below and adjacent said trailing edge flap when said trailing edge flap is in said high speed position, and an extended high lift vane position ahead of said trailing edge flap in which the trailing portion of said vane is spaced from a surface portion of said trailing edge flap adjacent to said upstream edge to define first converging slot walls therebetween for fluid flows from below said wing and across said first slot, said vane being further positioned with respect to said wing with the upstream leading portion of said vane being spaced from said undersurface of said wing to define second converging slot Walls therebetween for fluid flows from below said wing and across said second slot when said trailing edge flap is in said high lift position.

2. The structure of claim 1 characterized further in that said vane in said extended position has a third converging slot in and across said vane between said trailing portion of said vane and said leading portion of said vane for fluid flow from below said Wing across said third slot.

3. The structure of claim 1 in which said trailing edge flap has a recession in its undersurface into which said vane is accommodated in said retracted vane position.

4. The structure of claim 1 in which said wing trailing edge portion has a lower lip, an upper lip and a recession therebetween, with said vane in said retracted position being located above said lower lip, and below the high speed position of said trailing edge flap.

5. The structure of claim 1 in which said flap and said vane in said retracted vane position are closely mated to each other in a combined body arrangement of decreased volume. i

References Cited by the Examiner UNITED STATES PATENTS 2,157,281 5/39 Coanda. 2,836,380 5/58 Pearson 24442 2,9 12,190 11/59 MacDonough 24444 2,934,223 8 4/ 60 MacIntyre 24444 2,990,140 6/61 Mazelsky 24442 3,041,014 6/62 Gerin 24442 3,089,666 5 63 Quenzler 244-42 X 3,126,173 3 64 Alvarez-Calderon 24442 3,128,966 4/ 64 Alvarez-Calderon 24442 FOREIGN PATENTS 693,899 7/40 Germany.

987,021 4/51 France. 1,003,096 11/51 France.

MILTON BUCHLER, Primary Examiner. 

1. AN AIRCRAFT WING HAVING A TRAILING EDGE PORTION WITH AN UNDERSURFACE; A TRAILING EDGE FLAP MOUNTED ON SAID WING AND ADAPTED TO BE MOVED BETWEEN A HIGH SPEED POSITION IN WHICH SAID TRAILING EDGE FLAP IS FAIRED WITH SAID WING ADJACENT TO SAID TRAILING EDGE PORTION AND A HIGH LIFT POSITION INCLINED TO AND EXTERNAL FROM SAID WING WITH SAID TRAILING EDGE FLAP IN SAID HIGH LIFT POSITION HAVING AN UPSTREAM EDGE, AN UPPER SURFACE AND A LOWER SURFACE; A VANE MOUNTED ON SAID TRAILING EDGE FLAP BY MEANS OF A BRACKET EXTENDING FROM SAID VANE AND PIVOTED TO SAID FLAP AT A SPANWISE PIVOTAL AXIS LOCATED ADJACENT TO SAID UPSTREM EDGE, WITH SAID VANE BEING ADAPTED TO BE MOVED WITH RESPECT TO SAID TRAILING EDGE FLAP BY ANGULAR MOTION ABOUT SAID PIVOTAL AXIS WHICH INVERTS SAID VANE BETWEEN A RETRACTED VANE POSITION IN WHICH SAID VANE IS TRAILING SAID UPSTREAM EDGE AND IS LOCATED BELOW AND ADJACENT SAID TRAILING EDGE FLAP WHEN SAID TRAILING EDGE FLAP IS IN SAID HIGH SPEED POSITION, AND AN EXTENDED HIGH LIFT VANE POSITION AHEAD OF SAID TRAILING EDGE FLAP IN WHICH THE TRAILING PORTION OF SAID VANE IS SPACED FROM A SURFACE PORTION OF SAID TRAILING EDGE FLAP ADJACENT TO SAID UPSTREAM EDGE TO DEFINE FIRST CONVERGING SLOT WALLS THEREBETWEEN FOR FLUID FLOWS FROM BELOW SAID WING AND ACROSS SAID FIRST SLOT, SAID VANE BEING FURTHER POSITIONED WITH RESPECT TO SAID WING WITH THE UPSTREAM LEADING PORTION OF SAID VANE BEING SPACED FROM SAID UNDERSURFACE OF SAID WING TO DEFINE SECOND CONVERGING SLOT WALLS THEREBETWEEN FOR FLUID FLOWS FROM BELOW SAID WING AND ACROSS SAID SECOND SLOT WHEN SAID TRAILING EDGE FLAP IS IN SAID HIGH LIFT POSITION. 